The present invention relates to effecting an inventory of local devices by sound.
When a person first enters an unfamiliar work space, it is useful for that person to know what devices are present in the space and often the person will spend the first few minutes looking around, effectively carrying out an inventory of the devices present.
It is an object of the present invention to provide a user-friendly way of ascertaining what devices are present locally.
As will become clear below, certain embodiments of the present invention use a collision-detection and back-off protocol. Such protocols are themselves well known in the networking art; thus the access control protocol used by Ethernet and IEEE 802.3 networks is one such protocol, it being normally termed a CSMA/CD (xe2x80x9cCarrier Sense Multiple Access/Collision Detectionxe2x80x9d) protocol. In such a network protocol, a device wishing to transmit on the network first listens to see if any other device is transmitting (this is the xe2x80x9ccarrier sensexe2x80x9d)xe2x80x94if no other device is currently transmitting, the device commences to transmit. However, since two devices may do this at substantially the same time, a transmitting device listens out for collisions of its transmissions with those of another device. Where such a collision is detected, the device stops transmission and backs off (that is, does not consider re-transmitting) for a randomly chosen time period. In Ethernet networks, this time period is chosen according to a binary exponential backoff policy.
According to one aspect of the present invention, there is provided a method of effecting an inventory of local devices, involving:
(a) issuing a prompt to the devices;
(b) at each device, responding to the prompt by announcing the presence of the device by sound;
(c) the devices interacting to order their announcements so that each device announcement is, at least in due course, made uninterrupted by announcements from other devices.
Step (c) will typically involve the devices using a collision-detection and back-off protocol in respect of emissions from each other. These emissions are preferably the sound announcements themselves though other device emissions can alternatively be used for running the protocol.
According to another aspect of the present invention, there is provided a device provided with an announcement arrangement comprising
prompt detection means for detecting a broadcast prompt;
audio output means for announcing the presence of the device by sound; and
announcement control means for interacting with nearby devices having similar announcement arrangements such that, at least in due course, each device makes its announcement, through its audio output means, uninterrupted by announcements from other of the said devices.